Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction
A.2. below):

¨

Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

Sprint Nextel Corporation (NYSE: S) filed on December 13, 2012, a Schedule 13D with the Securities and Exchange Commission, in which it disclosed its intent to acquire shares of Clearwire
Corporations (the Company or Clearwire) capital stock it does not already own.

Clearwire is currently in
discussions with Sprint regarding a potential strategic transaction. A Special Committee of the Clearwire Board of Directors, previously formed to review potential indications or proposals, including from Sprint, has been reviewing the potential
strategic transaction. On December 12, 2012, Sprint submitted a non-binding proposal that had been reviewed by its Board of Directors, which included a purchase price for the remaining shares of Class A common stock and Class B common
stock (and related Clearwire Communications LLC units) of Clearwire it does not already own.

Clearwire does not comment on ongoing
negotiations with counterparties and, under the direction of the Special Committee, continues to be in discussions with Sprint to explore a transaction. There can be no assurance as to the terms of any potential transaction or that any transaction
will result.

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.